In-situ desulfurization of a feed stream in a catalytic reactor

Abstract

The present invention relates to a method for removing a sulfur containing catalyst poison from a feedstock. Benefits from removing catalyst poisoning sulfur compounds in a feedstock include upgrading the quality of the various petroleum fractions and prolonging the life of the catalyst. A preferred embodiment of the present invention includes adding a sacrificial metal to a Fischer-Tropsch reactor. The role of the sacrificial metal is adsorption of the sulfur-containing species that may deactivate or poison the catalyst.

What is claimed is:  
     
         1 . A method for extending the life of a catalyst that includes a catalytic metal, the method comprising: 
 a) selecting a sacrificial metal having a poison affinity at least equal a predetermined poison affinity;    b) providing a catalyst material comprising the sacrificial metal and the catalytic metal; and    c) contacting a feed stream with the catalyst material, wherein the feed stream comprises the poison.    
     
     
         2 . The method according to  claim 1  wherein the poison comprises sulfur.  
     
     
         3 . The method according to  claim 2  wherein the feed stream comprises not more than 10 ppm sulfur.  
     
     
         4 . The method according to  claim 2  wherein a pK sp  of a sulfur compound of the sacrificial metal is at least equal to a predetermined pK sp .  
     
     
         5 . The method according to  claim 4  wherein the predetermined pK sp  is about 25.  
     
     
         6 . The method according to  claim 2  wherein a pK sp  of a sulfur compound of the sacrificial metal is at least equal to a pK sp  of a sulfur compound of the catalytic metal.  
     
     
         7 . The method according to  claim 1  wherein at least a portion of the poison binds to the sacrificial metal.  
     
     
         8 . The method according to  claim 7  wherein at least 50 wt % of the poison binds to the sacrificial metal.  
     
     
         9 . The method according to  claim 1  wherein the sacrificial metal comprises a metal selected from the group consisting of bismuth, indium, mercury, thallium, calcium, copper, magnesium, silver, tin, antimony, cadmium, lead, molybdenum, tungsten, and combinations thereof.  
     
     
         10 . The method according to  claim 1  wherein the catalytic metal comprises a metal selected from the Group consisting of the elements of Group 8, the elements of Group 9, and the elements of Group 10.  
     
     
         11 . The method according to  claim 10  wherein the catalytic metal comprises cobalt.  
     
     
         12 . The method according to  claim 11  wherein the cobalt to sacrificial metal ratio is 2:1.  
     
     
         13 . The method according to  claim 1  wherein step (b) comprises mixing the sacrificial metal and the catalytic metal.  
     
     
         14 . The method according to  claim 13  wherein the step (b) comprises forming an intimate mixture of the sacrificial metal and the catalytic metal.  
     
     
         15 . The method according to  claim 14  wherein step (b) comprises impregnating the sacrificial metal and the catalytic metal on a support.  
     
     
         16 . The method according to  claim 13  wherein step (b) comprises forming a physical mixture of the sacrificial metal and the catalytic metal.  
     
     
         17 . The method according to  claim 16  wherein step (b) comprising impregnating the sacrificial metal supported on a first support and impregnating the catalytic metal on a second support.  
     
     
         18 . A process for producing hydrocarbons, comprising contacting a feed stream comprising hydrogen and carbon monoxide with a catalyst system that includes a sacrificial metal and a catalytic metal in a reaction zone maintained at conversion-promoting conditions effective to produce an effluent stream of hydrocarbons.  
     
     
         19 . The process according to  claim 18  wherein the feed stream comprises a poison.  
     
     
         20 . The process according to  claim 19  wherein the poison comprises sulfur.  
     
     
         21 . The process according to  claim 20  wherein the feed stream comprises not more than 10 ppm sulfur.  
     
     
         22 . The method according to  claim 20  wherein a pK sp  of a sulfur compound of the sacrificial metal is at least equal to a predetermined pK sp .  
     
     
         23 . The method according to  claim 20  wherein the predetermined pK sp  is about 25.  
     
     
         24 . The method according to  claim 20  wherein a pK sp  of a sulfur compound of the sacrificial metal is at least equal to a pK sp  of a sulfur compound of the catalytic metal.  
     
     
         25 . The method according to  claim 19  wherein at least a portion of the poison binds to the sacrificial metal.  
     
     
         26 . The method according to  claim 25  wherein the effluent stream comprises not more than 5 ppm poison.  
     
     
         27 . The process according to  claim 18  wherein the catalytic metal comprises a metal selected from the Group consisting of the elements of Group 8, the elements of Group 9, and the elements of Group 10.  
     
     
         28 . The process according to  claim 27  wherein the catalytic metal comprises cobalt.  
     
     
         29 . The process according to  claim 28  wherein the cobalt to sacrificial metal ratio is 2:1.  
     
     
         30 . The process according to  claim 18  wherein the sacrificial metal comprises a metal selected from the group consisting of bismuth, indium, mercury, thallium, calcium, copper, magnesium, silver, tin, antimony, cadmium, lead, molybdenum, tungsten, and combinations thereof.  
     
     
         31 . The process according to  claim 18  wherein the catalyst system comprises an intimate mixture of the sacrificial metal and catalytic metal.  
     
     
         32 . The process according to  claim 18  wherein the catalyst system comprises a physical mixture of the sacrificial metal and catalytic metal.  
     
     
         33 . A catalyst system for sulfur removal in a Fisher-Tropsch feed stream comprising: 
 a catalyst system comprising a sacrificial metal and a catalytic metal, wherein said sacrificial metal has a sulfur affinity at least equal to the catalytic metal's sulfur affinity.    
     
     
         34 . The catalyst system according to  claim 33  wherein the sulfur affinity is measured by a pK sp  of a compound of sulfur and the sacrificial metal.  
     
     
         35 . The catalyst system according to  claim 33  wherein the feed stream comprises 10 ppm sulfur.  
     
     
         36 . The catalyst system according to  claim 33  wherein said sacrificial metal is adapted to bind to said sulfur.  
     
     
         37 . The catalyst system according to  claim 36  wherein said sacrificial metal is adapted to bind at least 50 wt % of said sulfur.  
     
     
         38 . The catalyst system according to  claim 33  wherein the catalytic metal comprises a metal selected from the Group consisting of the elements of Group 8, the elements of Group 9, and the elements of Group 10.  
     
     
         39 . The catalyst system according to  claim 38  wherein the catalytic metal comprises cobalt.  
     
     
         40 . The catalyst system according to  claim 39  wherein the cobalt to sacrificial metal ratio is 2:1.  
     
     
         41 . The catalyst system according to  claim 33  wherein the sacrificial metal comprises a metal selected from the group consisting of bismuth, indium, mercury, thallium, calcium, copper, magnesium, silver, tin, antimony, cadmium, lead, molybdenum, tungsten, and combinations thereof.  
     
     
         42 . The catalyst system according to  claim 33  wherein the catalyst system comprises an intimate mixture of the sacrificial metal and catalytic metal.  
     
     
         43 . The catalyst system according to  claim 33  wherein the catalyst system comprises a physical mixture of the sacrificial metal and catalytic metal.